My favorite response to those people, in person or online, is "but how do you KNOW?" (they ALWAYS say the Bible) "But...there are so many versions, so many translations, How can that be the unfiltered, unadulterated Word of God? Do you read ancient Hebrew? Or maybe the old Greek?"

A few rounds of that usually sends them off, muttering to themselves in frustration.

Of course, if they get belligerent, I pull the 1st & 2nd Amendment line if it's in person...that ends the argument too.